This invention relates to gas turbine engines and, more particularly, to a gas turbine engine having a variable area fan nozzle for controlling thrust reversal of the gas turbine engine.
Gas turbine engines are widely known and used for power generation and vehicle (e.g., aircraft) propulsion. A typical gas turbine engine includes a compression section, a combustion section, and a turbine section that utilize a primary airflow through the engine to generate power or propel the vehicle. The gas turbine engine is typically mounted within a housing, such as a nacelle. A bypass airflow flows through a passage between the housing and the engine and exits from the engine at an outlet.
Presently, conventional thrust reversers are used to generate a reverse thrust force to slow forward movement of a vehicle upon landing, such as an aircraft. One type of conventional thrust reverser utilizes a moveable cowl mounted near the rear of the nacelle. After touch-down of the aircraft for landing, the cowl moves aft and radially inward from a stowed position to a position aft of the outlet of the bypass airflow passage to block the bypass airflow. In this position, the cowl deflects the bypass airflow in a forward direction to produce the thrust reversing force. Although effective, this and other conventional thrust reversers have only a single thrust reversal position and, therefore, have the disadvantage of providing only limited control over the amount of thrust reversing force. Moreover, when not in use during landing, the thrust reversers do not provide additional functions when in the stowed position. Therefore, there is a need for a thrust reverser that provides more control over the thrust reversing force and additional functionality outside of landing.